Significance turbidity

Without an artificial sink, the membrane retentions are very high, with many basic probe molecules showing R > 80%. With the imposed sink, many of the retentions dropped by as much as 50%. Furthermore, just 0.5% wt/vol cholesterol in dodecane (in addition to the sink) caused increased retention to drop by at least a further 10-30%. It was not possible to form stable cholesterol-containing lipid models under sink conditions with Avanti s egg lecithin acceptor buffer solutions turned significantly turbid in the untenable model 13.1. 

It is essential to have good stirring during this step. If the reaction mixture becomes significantly turbid, a change to mechanical stirring is advisable. 

Ozone in the gas phase can be deterrnined by direct uv spectrometry at 254 nm via its strong absorption. The accuracy of this method depends on the molar absorptivity, which is known to 1% interference by CO, hydrocarbons, NO, or H2O vapor is not significant. The method also can be employed to measure ozone in aqueous solution, but is subject to interference from turbidity as well as dissolved inorganics and organics. To eliminate interferences, ozone sometimes is sparged into the gas phase for measurement. 

Table 1 Hsts a number of common inorganic coagulants. Typical iron and aluminum coagulants are acid salts that lower the pH of the treated water by hydrolysis. Depending on initial raw water alkalinity and pH, an alkah such as lime or caustic must be added to counteract the pH depression of the primary coagulant. Iron and aluminum hydrolysis products play a significant role in the coagulation process, especially in cases in which low turbidity influent waters benefit from the presence of additional colHsion surface areas.

Polymerization-grade chloroprene is typically at least 99.5% pure, excluding inert solvents that may be present. It must be substantially free of peroxides, polymer [9010-98-4], and inhibitors. A low, controlled concentration of inhibitor is sometimes specified. It must also be free of impurities that are acidic or that will generate additional acidity during emulsion polymerization. Typical impurities are 1-chlorobutadiene [627-22-5] and traces of chlorobutenes (from dehydrochlorination of dichlorobutanes produced from butenes in butadiene [106-99-0]), 3,4-dichlorobutene [760-23-6], and dimers of both chloroprene and butadiene. Gas chromatography is used for analysis of volatile impurities. Dissolved polymer can be detected by turbidity after precipitation with alcohol or determined gravimetrically. Inhibitors and dimers can interfere with quantitative determination of polymer either by precipitation or evaporation if significant amounts are present. 

Molten chromic acid decomposes at its melting point at a significant rate. The lower oxides formed impart darkness and turbidity to the water solution. Accordingly, both temperature and time are important in obtaining a quaHty product. 

Table 4 summarizes the efficiency of membrane filtration as preliminary treatment in the hybrid process to obtain regenerated water for industrial reuse. Working with the adequate cleaning cycle to avoid fouling and to keep a constant flux (10 1 min ) important reduction in suspended solids (90%) and turbidity (60%) of the wastewaters is achieved but there is no significant reduction of other chemical or physical parameters, e.g., conductivity, alkalinity or TDS, or inactivation of E. coli. 

The significant increases in the turbidity of AgN03 solution could be due to the formation of colloidal solution of silver as also reported earlier by other researchers [60]. As evident from our data (Table 9.1), the increase in the turbidity could either be due to the formation of AgOH from Ag+ or possibly Ag° particles. Upon the addition of NH3, the formation of [Ag(NH3)2]+ in water itself could also be possible. 

Sonication of 25 ml of 0.25 M aqueous solution of Pb(N03)2 increased the turbidity and conductivity of these solutions significantly along with the rise in temperature (Table 9.3). The increase in turbidity of the solution could be attributed... 

In the analysis of seawater, the only significant interference arises from turbidity caused by particles in the sample. Prior filtration of the sample is therefore necessary. For anoxic waters, however, sulfide concentrations over 2 pm were found to decrease the absorbance. This was overcome by adding an excess of either Cd2+ or Hg2+ to the sample [171,172],... 

Turbidity caused by the presence of lipid results in significant light scattering. If not taken into consideration, in spectrophotometry-based hemoglobin estimation, the latter leads to erroneous interpretation. 

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